use std::io::Write;
/// Enum representing all possible values the application can fail.
#[derive(Debug, Clone, Hash, PartialEq, Eq)]
pub enum Outcome {
/// No errors occured, everything executed correctly.
NoError,
/// The specified file would need to be overriden but was not allowed to.
OverrideNoForce(String),
/// The specified subsystem needs to be run beforehand to produce the specified file.
RequiredFileFromSubsystemNonexistant {
/// The subsystem that needs to be run.
subsys: &'static str,
/// The file the specified subsystem produces.
fname: String,
},
/// The specified subsystem needs to be run beforehand to produce the specified data.
RequiredDataFromSubsystemNonexistant {
/// The subsystem that needs to be run.
subsys: &'static str,
/// The description of what needs to be produced.
desc: String,
},
/// The Twitter API returned an error.
TwitterAPIError(String),
/// Failed to parse the specified file because of the specified errors.
FileParsingFailed {
/// The file that failed to parse.
desc: &'static str,
/// The parsing errors that occured.
errors: Vec<String>,
},
}
impl Outcome {
/// Get the executable exit value from an `Outcome` instance.
///
/// # Examples
///
/// ```
/// # use tweetr::Outcome;
/// # use std::iter::FromIterator;
/// let mut out = Vec::new();
/// Outcome::OverrideNoForce("doctest".to_string()).print_error(&mut out);
/// assert_eq!(String::from_iter(out.iter().map(|&i| i as char)),
/// "File \"doctest\" was not overriden to prevent data loss.\n\
/// Pass --force to override it.\n".to_string());
/// ```
pub fn print_error<W: Write>(&self, err_out: &mut W) {
match *self {
Outcome::NoError => (),
Outcome::OverrideNoForce(ref fname) => {
writeln!(err_out, "File \"{}\" was not overriden to prevent data loss.", fname).unwrap();
writeln!(err_out, "Pass --force to override it.").unwrap();
}
Outcome::RequiredFileFromSubsystemNonexistant { ref subsys, ref fname } => {
writeln!(err_out, "Run the {} subsystem first to produce \"{}\".", subsys, fname).unwrap()
}
Outcome::RequiredDataFromSubsystemNonexistant { ref subsys, ref desc } => {
writeln!(err_out, "Run the {} subsystem first to {}.", subsys, desc).unwrap()
}
Outcome::TwitterAPIError(ref error) => writeln!(err_out, "Twitter API error: {}", error).unwrap(),
Outcome::FileParsingFailed { ref desc, ref errors } => {
writeln!(err_out, "Failed to parse {}{}", desc, if errors.is_empty() { '.' } else { ':' }).unwrap();
for err in errors {
writeln!(err_out, " {}", err).unwrap()
}
}
}
}
/// Get the executable exit value from an `Outcome` instance.
///
/// # Examples
///
/// ```
/// # use std::process::exit;
/// # use tweetr::Outcome;
/// exit(Outcome::NoError.exit_value());
/// ```
pub fn exit_value(&self) -> i32 {
match *self {
Outcome::NoError => 0,
Outcome::OverrideNoForce(_) => 1,
Outcome::RequiredFileFromSubsystemNonexistant { .. } |
Outcome::RequiredDataFromSubsystemNonexistant { .. } => 2,
Outcome::TwitterAPIError(_) => 3,
Outcome::FileParsingFailed { .. } => 4,
}
}
}